This invention relates generally to inking devices for intaglio printing devices and particularly to such a device having a removeable inking bar cartridge.
Intaglio printing is a technique of printing bar codes on nonporous objects and is well known in the art, as exemplified by U.S. Pat. Nos. 4,473,008 and 4,530,286. Typically in such printing, a smooth inking surface contains a substantially rectangular aperture. A plurality of substantially flat inking bars are stacked together and are arranged along one dimension of the aperture such that the combined thicknesses of the bars substantially fill the aperture. The inking bars include an inking surface which spans the other dimension of the aperture such that the inking surfaces substantially fill the other aperture dimension. The inking bars have a thickness which is determined by the desired width of the bars in the bar code to be printed. The entire inking surface, including the inking edges of the bars, are covered with ink by a mechanical member which drags ink from a reservoir across the inking surface. A squeegee like member is used to remove ink from the printing surface. Prior to inking the inking surface, selected inking bars are depressed to lie a small distance below the inking surface to form cavities between the nondepressed bars. Ink fills the cavities and remains in the cavities after the ink is removed from the inking surface. A nonporous, resilient member is depressed against the inking bars and enters the cavities to transfer the ink from the cavities to the resilient member. The resilient member is removed from the inking surface and brought into contact with the object upon which the bar code is to be printed to effect the transfer of the ink from the resilient member to the item to be identified.
Mechanisms for bar coding nonporous objects in the above-described manner are well known in the art as exemplied by the above-referenced U.S. patents. However, difficulties are encountered because the ink has a tendency to seep between the inking bars, necessitating frequent cleaning of the inking bars and the associated mechanism. Typically, such cleaning requires removal of the inking bars and individually cleaning each of the bars. During such cleaning the inking mechanism is inoperative and cannot be used in the asssembly line. For this reason there is a need for an inking mechanism which is readily removeable from the printing mechanism to minimize the down time of the mechanism during cleaning. There is also a need for a printing bar configuration which enhances the elimination of ink from between the inking bars to prolong the operating time between cleaning periods. There also is a need for an inking bar detenting mechanism which is compact and which minimizes the number of detent actuating means. The present invention fulfills these needs.